Biodegradable packaging for shipping

ABSTRACT

A biodegradable, thermally insulated mailer and cooler, and method of making them, are disclosed. The thermally insulated packaging material are made from laminated starch foam and bio-plastic film. The lamination can be performed by heat bonding, without the use of an adhesive bonding agent, to produce biodegradable packaging materials that can pass ASTM and other certifications for home compostability and marine environment safety.

TECHNICAL FIELD OF THE INVENTION

The present invention generally relates to biodegradable packaging forshipping, and, more specifically, to biodegradable shipping envelopes,coolers, and the like for shipping temperature-sensitive materials.

BACKGROUND OF THE INVENTION

The shipping and mailing industry offers a wide range of products andservices today in order to provide efficient and effectivetransportation of a wide range of cargoes via both private carriers andthe federal postal system. These products include a large variety ofpackaging designed to protect valuable cargoes, from impact, crushing,spoilage, and so forth.

Cargoes that are thermally sensitive have been a substantial and growingportion of the cargoes being shipped. Such cargoes include, for example,food products, such as sea foods, and a variety of medical products,including insulin or insulin replacements. The ability to package suchcargoes so that the shipper can be assured that the products will remainadequately refrigerated for 48 to 72 hours greatly improves the economywith which such products can be shipped, because it obviates the needfor overnight shipping, and allows handling of such packages accordingto more standard shipping practices. This greatly reduces the overallcost of the shipping, as long as the cost of the packaging remainsrelatively modest. Thus, this sector of the shipping industry has been arapidly expanding sector.

Unfortunately, existing products that have facilitated the shipping oftemperature-sensitive cargoes tend to be especially problematic for theenvironment. For example, expanded polystyrene (e.g. Styrofoam®)packaging, a common insulating material, is problematic in terms of bothits production and disposal (it includes benzene; furthermore, itoutgases, which can be dangerous in and of itself, and causes it toloose R-value). It requires nearly 700 gallons of oil to produce one tonof expanded polystyrene, it generally cannot be economically recycled,it is generally lethal to any creature that ingests a significantquantity, and, in the absence of expensive procedures (which, as apractical matter, are never employed) it does not decompose in anyreasonable time period.

Biodegradable alternatives to expanded polystyrene have been developed,but they remain generally unacceptable alternatives. For example, PLA(polylactic acid) is for at least some applications a suitable drop-inreplacement for polystyrene. However, it will biodegrade only incommercial facilities, and it suffers from manufacturinginconsistencies, especially in the manufacturing of thicker sheets,which render it unacceptable for many packaging applications. Foranother example, foam made from corn starch exists, but it is generallyunacceptable as shipping material, both because contact with moisturecauses the material to degrade, and because the material in its dry form“sands,” i.e., it abrades, damaging the structural integrity of thematerial and producing small particulate waste. In addition to theresulting structural degradation, the resulting waste is problematic,both aesthetically and from a practical perspective. There is,therefore, a substantial need in the industry for acceptable materialsfor shipping thermally sensitive cargoes which do not pose environmentalproblems. The present invention is directed to meeting this need.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a first embodiment shipping envelope, shownbefore assembly.

FIG. 2 is a diagram of a first embodiment shipping envelope, shown afterassembly and before sealing.

FIG. 3A is a diagram of a composite made by laminating multiple sheetsof biodegradable foam, suitable for making a second embodimentbiodegradable cooler.

FIG. 3B shows a joint in a composite sheet suitable for forming thecorner of a second embodiment biodegradable cooler or box-liner.

FIG. 4A is a plan view of a top for a second embodiment biodegradablecooler or box-liner.

FIG. 4B is a side view of a top for a second embodiment biodegradablecooler or box-liner.

FIG. 5 is a perspective view of a second embodiment biodegradable coolerwith the top removed.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, and alterations and modifications in theillustrated devices and methods, and further applications of theprinciples of the invention as illustrated therein are hereincontemplated as would normally occur to one skilled in the art to whichthe invention relates.

The United States has adopted standards defining test standards forlabeling a product “biodegradable and compostable,” ASTM D6400. Thisstandard establishes a standard of industrial compostability, but thisstandard only establishes compostability at temperatures higher than aretypically achieved in private composting. Consequently, products thatsatisfy this standard may not properly break down if consumers put themin their home compost heaps. Products that will break down in thetypical conditions of a private compost heap are therefore desirable.Nonetheless, the U.S. has not adopted standards for labeling a product“home compostable.” Europe has adopted some such standards, but theyvary by region. Although bio-degradability and compostability arecurrently established by separate standards in Europe, for the purposeof this document the term “bio-degradable” will be used to refergenerally to the class of environmentally friendly standards, withoutdistinction.

In view of present public attention to the subject, it is expected thatthe United States will adopt the standard employed by the EuropeanUnion, known as EN 13432, or a comparable standard, forbio-degradability. That standard requires that 90% of the product, bymass, is converted to CO2 within 6 months, and that after 3 months ofcomposting and subsequent sifting through a 2 mm sieve no more than 10%residue, by mass, remains. Composite packaging materials satisfy thisstandard only if every component from which they are made satisfiesthese criteria. Thus, for example, a composite packaging material madefrom a substrate that is 99% converted to CO2 and a surfacing agent thatis only 85% converted to CO2 cannot be rendered “biodegradable” merelyby changing the proportions of the mass of the substrate and surfacingagent. Composite packaging materials according to the disclosedembodiments have been found to meet the EN 13432 standard, and aretherefore acceptable for labeling as “biodegradable” and “compostable”for shipping to Europe.

Although newer and better biodegradable and compostable materials arebeing developed all the time, existing biodegradable materials stilllack physical characteristics of the packaging materials that we areseeking to replace. For example, bio-plastic films that might otherwisereplace conventional plastics are weak, tend to tear, and to propagatetears once formed. This tends to render them unsuitable for manycommercial shipping applications.

Similarly, corn starch foam is biodegradable and compostable, and canprovide suitable insulation for general purpose thermal-sensitiveshipping packaging. It will be appreciated by those skilled in the art,however, that corn starch foams are not generally acceptable insulatorsfor shipping applications. In their dry form, and unlike expandedpolystyrene and other such petroleum-based products, corn starch foamstend to “sand.” That is, when the material rubs against itself or itsenvironment, it tends to abrade, producing sand-like particles, anderoding the material. Furthermore, contact with any moisture, such asthe condensation that develops when a cooled package is exposed to highhumidity, causes the material to degrade. This can completely destroythe thermally insulating properties.

It has been discovered, however, that corn starch foams can be renderedsuitable for shipping applications by protecting it within a film thatprotects the material from moisture and from friction with thesurrounding environment. Potential organic films include cellulose-basedfilms, starch, PLA (polylactic acid) films, and PHA(polyhydroxyalkanoate) films. PCL, or polycapralactones, PVA, orpolyvinylalcohol, and EVOH, or ethylene vinyl alcohol, arepetroleum-based but biodegradable films, that would also be potentialcandidates. A suitable film must be sufficiently strong to resisttearing or breaking, and ideally, will not propagate tears once started.More importantly, in order for the resulting packaging to retain itsbiodegradable properties, the protective film must, of course, itself bebiodegradable.

Bioplastic films provide a suitable film for enclosing corn starch foamto provide biodegradable and home-compostable packaging for shipping.For example, a favorable result can be provided by the use ofpotato-based bioplastic film. For one example, a particularly suitablepotato-based bioplastic is LTBio, produced by and available from CeeTUK, 31 Mount Street, Manchester, M27 5NG, United Kingdom. Other suitablefilms are commercially available from Danimer Scientific, 1301 ColquittHighway, P.O. Box 7965, Bainbridge, Ga. 39818 (www.danimer.com), andBiome Technologies, North Road, Marchwood Industrial Park, Marchwood,Southampton, UK SO40 4BL (www.biometechnologiesplc.com). Packaging thatcombines corn starch foams and organic bioplastic films have been foundto sufficiently degrade within 90 to 180 days, when in contact with themicroorganisms commonly found in the ground, and especially in compostenvironments. However, such composite materials are sufficientlyresistant to water and other environmental factors to maintain theirintegrity for at least 7 days. As such, these composites provide for theconstruction of commercially acceptable packaging for shipping, yetconform to the highest standards of biodegradability presently in force(including “aerobic biodegradability in a marine environment,” ASTMD6691).

While enclosing the corn starch foam in such a potato-based film canprovide functional packaging, it will be appreciated that the film needsto be adhered to the underlying foam substrate. This process isgenerally performed by a wet laminator. A film and substrate are fedinto the laminating machine with a heat-activated bonding agent thatadheres the two. Of course, in order for the resulting packaging toretain its biodegradable properties, the adhesive bonding agent used tobond the film to the substrate must itself be biodegradable. This posesa critical problem, as there is, at present, no known bonding agent thatis home compostable, and so there is no known way to laminate layers ina way that satisfies ASTM 6400 (for example). It has been discovered,however, that this problem can be overcome by heat bonding a specificstarch film to a specific film, without any bonding agent. Surprisingly,the combination of the specific film and substrate react to the heat toproduce a heat bond directly, with no need for the bonding agent that isusually required.

The desired corn starch foam is an extruded, high amylose content foam,at least about 90% corn starch, by weight. The high amylose contentprovides for greater strength and flexibility. A suitable non-GMO cornstarch foam is Green Cell Foam™, provided by KTM Industries, 3327 RangerRd., Lansing, Mich. 48906 (www.ktmindustries.com). Green Cell Foam™ istypically sold in corrugated, extruded planks.

The desired film is a bio-based biodegradable bio-plastic. Althoughhigher carbon-neutral content is desirable, petroleum-based bio-plasticsare acceptable, as long as they have the other desired features. Theideal film is Danimer 12291, a bio-polymer resin film that is that soldby Danimer Scientific, 1301 Colquitt Highway, P.O. Box 7965, Bainbridge,Ga. 39818 (www.danimer.com). Danimer 12291 is a compostable (testedaccording to ASTM D6400-04, EN 14332 (2000), and ISO 17088 (2008)standards), sold for such applications as trash bags, agricultural mulchfilm, greenhouse films, compost bags, hay bale wraps, etc. Danimer'sfilm is unique, at the moment, in that it is certified as safely“biodegradable in marine environments.” (The certification is byExperimental Station Scientific Paper, Carboard and Pulp, or SSCCP, ofMilan. It has not yet been certified under the ASTM standard, in partbecause the standard was adopted after SSCCP certification wasinitiated; it is believed that it also satisfies the ASTM standard, andwill receive that certification in due course. Note that its renewablebio-content is about 30%—the remainder is made up of a biodegradablepetroleum based material.)

The corn starch foam is compressed into a thin, flexible sheet—referredto as “paper”—by rolling it through rollers. (The rollers are arrangedlike an old laundry wringer, or “mangle.”) Multiple sheets can belaminated together to create paper with a greater thickness, cushioning,insulation, etc., if desired. The corn starch paper is then die-cut,including desired perforations (such as for a tear-strip for opening themailer). The film and paper are then c-folded, with the film on eitherside of the paper, and run through the lamination machine without anadhesive bonding agent, to produce the composite paper. Application of afine water mist may assist in achieving a consistent bonding betweenpaper and film, but is not believed to operate as an adhesive. Thecomposite paper is then folded up to form the mailer. A paper tongue isinserted into the interior to prevent face-to-face heat sealing fromclosing the interior, and the mailer is re-run through the laminator.

The bonding of the film to the paper is sensitive to temperature and tothe speed with which the sheets are fed through the laminator.Obviously, it is desirable, for commercial reasons, to feed the sheetsat the highest practicable speed. However, higher temperatures arerequired to more rapidly bond the film to the paper. On the other hand,at a certain point, higher temperatures become counter-productive. Ithas been discovered through experimentation that the best bond isachieved with a laminator feed rate of 22 feet/s, and a bondingtemperature of 253° F. A suitable bond can be achieved with a feed rateof 31 feet/s and a bonding temperature of 253° F. An acceptable butinferior bond can be achieved with a feed rate of 36 feet/s and abonding temperature of 258° F. A less desirable bond still can beachieved with a feed rate of 36 feet/s and a bonding temperature of 248°F. Generally, the resulting bond will not be suitable unless the bondingtemperature is above about 225° F.

FIGS. 1 and 2 illustrates a first embodiment biodegradable shippingenvelope, indicated generally at 100, shown before and after assemblyinto an envelope, respectively. Side tabs 110 hold the side edges 122 ofthe front 120 to the side edges 132 of the back 130 to form a pouch. Atop tab 140 can be folded over to seal the envelope 100 (by any suitableadhesive means, such as a strip of double-sided tape along the topedge). The top tab advantageously includes a pull-strip 150, comprisingtwo parallel rows of perforations 151 and a small pull-tab 152, whichallows for easy opening of the sealed envelope 100.

In order to produce envelopes suitable for commercial applications, thefilm can advantageously be flexographically printed, using watersoluble, bio-degradable and/or compostable inks, prior to bonding to thepaper. Such printing advantageously includes a commercial graphic designincorporating information on the biodegradability and/or compostabilitystandards satisfied by the product, in addition to the vendor'strademark information.

It will be appreciated that a biodegradable composite film can be use tomake a variety of other shipping containers, as would occur to those ofskill in the art. For example, in another aspect, the composite papercan be cut in the same fashion as corrugated cardboard into the patternfor cardboard boxes, in order to make convenient, biodegradable boxesthat can be shipped, stacked, and otherwise used in the same fashion asa standard cardboard container. In this way, for example, convenientwine shippers can be made, including 1-, 3-, and 5-bottle wine shippers.In still another aspect, the composite paper can be used to make baitcontainers, such as are typically used by fishermen during recreationalfishing. In this context, biodegradability, especially in a marineenvironments, is a key advantage over existing bait containers.

FIG. 5 illustrates a first embodiment biodegradable shipping cooler 200,suitable for more voluminous or more temperature-sensitive cargoes. Thecooler 200 comprises four sides 210, a top 220, (shown in FIGS. 4A and4B) and a bottom 230, (not visible) each of which is formed from cornstarch foam panels. Typically, corn starch foams are extruded into ½inch corrugated sheets, and it will often be desirable for the panels tobe thicker than this, in order to provide the desired insulationproperties. When this is the case, the corn starch panels are formed bylaminating two or more sheets together (using a starch-based adhesive),to produce a composite material, illustrated in FIG. 3A, and indicatedgenerally at 300. The illustrated composite 300 comprises three cornstarch foam sheets 310 laminated together, and a fourth, “paper” sheet320, made by rolling a corn starch foam sheet and heat bonding a film,as described above, laminated to one side. The film side of the papersheet 320 will form the outside of the finished cooler 200.

The composite 300 is placed, film side-up, on a mitering table, and thefoam sheets are mitered to allow the composite to be “rolled up” intothe four sides of the cooler. By cutting away the foam, while leavingthe paper intact, the paper forms a “hinge”—a flexible connectionbetween the foam panels, which served both to seal a corner of theassembled cooler, and to hold the panels together to assist in theassembly of the cooler. It will be appreciated that the precise patterncut by the miter saw is not critical, but a simple, workable pattern isto cut the foam sheets into four equal panels, each having a simple 45degree miter on either side. This will produce a cubical cooler 200,but, again, this can be varied as desired.

The top 220 and bottom 230 are typically made from the same composite300 as the sides 210. While in theory, they could be attached to thesame paper substrate as the sides 210, in practice the corn starch foamis commercially available in a limited width (constrained by thedimensions of the extruding machinery), and this imposes an overalllimit on the size of the paper—typically 18 inches in maximum width.Consequently, the top 220 and bottom 230 must either be attached to thesides 210 by a separate paper sheet (meaning an additional laminatingpass that bonds the paper holding the side panels 210 together with apaper holding the top 220 and bottom 230), or they must remain aseparate piece. The latter option is suitable, for example, if thecooler is intended to be used as a box-liner, i.e., if the cooler isintended to add thermal insulation for a standard cardboard box.) Thetop 220 and bottom 230 are advantageously mitered to fit snugly againstthe edges of the sides 210. Preferably, though, these miter cuts are 90°cuts (to create an edge lip that prevents the top 220 and bottom 230from falling into the interior), so that matching miter cuts are notrequired along the top and bottom edges of side panels 210.

It will be appreciated that the biodegradable foam-film composite can beused to make biodegradable coolers in other ways, as would occur tothose of skill in the art. For example, a pair of 3-panel compositepieces can be used to add thermal insulation to a standard cardboard.The 3-planel composites are inserted to form 2 interlocking “C” forms toprovide thermal insulation for each of the box's six sides.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly the preferred embodiment has been shown and described and that allchanges and modifications that come within the spirit of the inventionare desired to be protected.

What is claimed is:
 1. A biodegradable mailer, made from a compositeconsisting essentially of: a corn starch foam paper; a bio-plastic filmthat is heat-bonded to the corn starch foam paper; compostable ink;wherein the compostable ink is used to present information aboutbiodegradability of the mailer.
 2. The biodegradable mailer of claim 1,wherein the petroleum based bio-plastic film is Danimer
 12291. 3. Thebiodegradable mailer of claim 1, wherein the corn starch foam paper ismade from Green Cell Foam™ by compressing it into a thin, flexiblesheet.
 4. The biodegradable mailer of claim 3, wherein the petroleumbased bio-plastic film is Danimer
 12291. 5. The biodegradable mailer ofclaim 1, wherein the film is heat-bonded to the corn starch paper at atemperature between about 248° F. and about 255° F., at a speed betweenabout 22 ft/s and about 40 ft/s.
 6. The biodegradable mailer of claim 5,wherein the temperature is between about 253° F. and about 258° F., andthe speed is about 31 ft/s and about 36 ft/s.
 7. A composite papercomprising: a compressed, flexible corn starch foam sheet; a bio-plasticfilm that is heat bonded to the corn starch paper, wherein no adhesiveis used to bond the corn starch film and the bio-plastic film.
 8. Amethod of making a biodegradable composite paper comprising: providing acompressed, flexible corn starch foam sheet; providing a bio-plasticfilm; adhering the corn starch foam sheet and the bio-plastic film byrunning them through a laminator, without an adhesive.
 9. The method ofclaim 8, wherein a fine water mist is applied in place of an adhesive toassist in achieving a consistent lamination between the foam and thefilm.
 10. The method of claim 8, wherein the foam is Green Cell Foam™.11. The method of claim 8, wherein the film is Danimer
 12291. 12. Abiodegradable cooler, comprising: corn starch foam panels; a bio-plasticfilm that is heat-bonded to the corn starch foam panels; wherein thebio-plastic film encloses the corn starch foam panels, and wherein noadhesive is used to bond the bio-plastic film.
 13. The biodegradablecooler of claim 12, wherein the corn starch film is Green Cell Foam™.14. The biodegradable cooler of claim 12, wherein the bio-plastic filmis Danimer
 12291. 15. The biodegradable cooler of claim 12, wherein thebioplastic film flexibly connects at least two of the corn starch panelsto one another to form a hinge.
 16. The biodegradable cooler of claim15, wherein the bioplastic film flexibly connects exactly three of thecorn starch panels, whereby the cooler can be assembled for use byinserting two 3-panel pieces into a standard box to form twointerlocking “C” forms.
 17. The biodegradable cooler of claim 13,wherein the corn start foam panels are formed by laminating multiplelayers of Green Cell Foam™ to one another to form at least 2″ thicksheets.
 18. A method of making biodegradable packaging comprising heatbonding corn starch foam and bio-plastic film without an adhesivebonding agent.
 19. The method of claim 18, wherein at least some of thecorn starch foam has been made into corn starch paper.
 20. The method ofclaim 19, wherein the heat bonding is performed by a lamination at atemperature between about 253° F. and about 258° F. and a speed of about31 ft/s and about 36 ft/s.